1. Field
Example embodiments relate to an organosilicon nanocluster, a silicon thin film including the same, a thin film transistor including the silicon thin film, a display device including the thin film transistor, and methods of forming the same. Other example embodiments relate to an organosilicon nanocluster in which a silicon cluster may be substituted with a conductive organic material, a silicon thin film including the same, a thin film transistor including the silicon thin film, a display device including the thin film transistor, and methods of forming the same.
2. Description of the Related Art
Amorphous silicon is a material of driving parts for solar cell and/or TFT-LCD technology, and research into applications thereof has been conducted. However, because the amorphous silicon is formed using a conventional vapor deposition method, there may be problems in that decreasing the manufacturing cost and producing relatively large-sized products may be difficult.
As an attempt to decrease the manufacturing cost and to produce relatively large-sized products, organic silane compounds have been researched as relatively high-functional organic materials. However, straight-chain polysilane, which is considered to overcome the problems, may have insufficient stability. Polysilane, which is a low-dimensional silane compound, may offer suitable semiconductor characteristics, but may lack effective means for p-n control. In one-dimensional materials, even if elements, e.g., phosphorus and/or boron, are introduced into main chains of the materials, only trap sites may be left in the material, thereby obtaining insufficient results. When the material is doped with Lewis acid or Lewis base, stability may be decreased. Straight-chain polysilane compounds may not be used as a silicon precursor because the main chains of the straight-chain polysilanes may be decomposed and then vaporized while organic groups may be separated from the straight-chain compounds.
Because network polysilane, which is a polysilane compound having branched silicon chains, is soluble in an organic solvent, a thin film may be more easily formed. However, because organic substitution groups of the thin film prevent or reduce a carrier from migrating between silicon backbones, the network polysilane may not exhibit improved semiconductor characteristics compared to the straight-chain polysilane compounds. Because the network polysilane has a network structure and thus has improved heat resistance, an amorphous silicon thin film may be formed through heat treatment. However, because the amorphous silicon thin film has many residual organic substitution groups, the amorphous silicon thin film may have undesirable electrical properties compared to original amorphous silicon, and there are no methods suitable for doping phosphorus and/or boron.
Amorphous silicon having the same effect as that obtained through conventional vapor deposition methods may be obtained by heating t-butyloctasilacubane used as a precursor. However, because the t-butyloctasilacubane, which is a crystalline compound, may form a thin film only through vapor deposition methods, the thickness of the formed thin film may also be nonuniform.
There are technologies for removing organic materials, in which soluble silicon cluster precursors may be prepared by synthesizing silicon clusters, a thin film may be formed on the precursors, and then the thin film may be heat-treated. However, removing organic materials and controlling defects derived from the removed organic materials may be relatively difficult, and the conductivity of the thin film may be decreased.